Trucks having open rear cargo bays are typically backed into alignment with a loading dock or other doorway to facilitate loading and unloading of the vehicle. A significant space is typically formed between the truck and the building which exposes the interiors of the building and the truck, and the workers and materials to the outside environment during loading and unloading. Attempts to seal the gap have included loading dock shelters and loading dock seals.
Conventional loading dock seals utilize resilient, compressible pad members, generally disposed at the lateral and top edges of the opening. The pad members are typically covered with coated fabric, vinyl or other similar coverings for protection and appearance. A seal is obtained by the engagement of the exterior walls or rear edges of the cargo bay of the truck directly against the seal. Loading dock seals are generally desirable when the incoming trucks are of a predictable size and configuration, and the seal may be placed so that it will routinely engage all portions of the rear or side of the incoming truck. Since many conventional dock shelters have rigid frames or portions of frames, they have been subject to impact damage from the trucks. Attempts to provide hinged or compressible frames have not been entirely satisfactory because they are still subject to damage, are relatively difficult to maintain and increase manufacturing costs. Similarly, the metal protective bumpers are expensive and cumbersome to install. Since many loading docks have inclined driveway grades, many loading dock shelters must be individually manufactured in order to accommodate such grades and maintain the proper perpendicular orientation between the truck walls and the curtains which also increases manufacturing costs.
Many conventional dock seals, dock shelters, and combined dock seals and shelters are relatively difficult to maintain. The compressible pads require the truck to exert considerable force on the pad and the building wall in order to obtain the proper sealing engagement, increasing abrasion and wear on the seal, particularly where the rear corners and edges of the truck rub against the material. The curtain in the dock shelter is similarly subject to wear and abrasion. They have also been unable to accommodate uneven truck surfaces, projecting hinges and the like and thus, have been unable to create an air tight seal.
Although it is desirable to seal the truck and the dock opening to prevent the escape of heated or air conditioned air during inclement weather, it is undesirable to do so during mild weather. Unfortunately, the seals and the curtains are typically disposed about the dock opening such that they can not be removed or adjusted to unseal the opening in such mild weather.